View single post by Mark Rosenbaum
 Posted: 06-26-2006 01:53 am
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Mark Rosenbaum

Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
IMHO the most likely possibilities are:
  • Fuel pressure at carburetors is too high (normal is 2.5 psi, upper limit is 3.0 psi, IIRC).
  • Incorrect reassembly of the start enrichment valve or 'choke'.
  • Vacuum valves sticking in the elevated position when you release the throttle.
  • Incorrect mixture needle in one or both carbs.
Once any problems are corrected, the float heights, mixtures, and carb balance will all need to be re-set.

The temp compensators lean out the mixture when the engine warms up, so, as you surmise, it's very unlikely they have anything to do with your problem.

While you are correct that worn throttle shaft seals (as well as worn throttle shafts) will result in a lean mixture, the seals are a primary wear item and they really should be replaced whenever a carb overhaul is performed.

For replacement carbs, IMHO the least expensive option is to find a spare set on eBay.  JH-specific Strombergs are easiest to deal with, of course, but those from many other cars can be made to work if the correct mixture needles and vacuum valve return springs are used.